Huge linear magnetoresistance due to open orbits in γ\gamma-PtBi2_2

Some single-crystalline materials present an electrical resistivity which decreases between room temperature and low temperatures at zero magnetic field as in a good metal and switches to a nearly semiconductinglike behavior at low temperatures with the application of a magnetic field. Often, this is accompanied by a huge and nonsaturating linear magnetoresistance which remains difficult to explain. Here we present a systematic study of the magnetoresistance in single-crystal $\gamma$-PtBi$_2$. We observe that the angle between the magnetic field and the crystalline $c$ axis fundamentally changes the magnetoresistance, going from a saturating to a nonsaturating magnetic field dependence. In between, there is one specific angle where the magnetoresistance is perfectly linear with the magnetic field. We show that the linear dependence of the nonsaturating magnetoresistance is due to the formation of open orbits in the Fermi surface of $\gamma$-PtBi$_2$.Comment: 12 pages, 8 figures including Supplementary Materia

Orden y desorden en superconductividad

Tesis doctoral inédita. Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Física de la Materia Condensada. Fecha de lectura: 19-06-0

Analysis of Four Polymorphisms Located at the Promoter of the Estrogen Receptor Alpha ESR1 Gene in a Population With Gender Incongruence

[Abstract] Introduction: Gender incongruence defines a state in which individuals feel discrepancy between the sex assigned at birth and their gender. Some of these people make a social transition from male to female (transwomen) or from female to male (trans men). By contrast, the word cisgender describes a person whose gender identity is consistent with their sex assigned at birth. Aim: To analyze the implication of the estrogen receptor a gene (ESR1) in the genetic basis of gender incongruence. Main Outcome Measures: Polymorphisms rs9478245, rs3138774, rs2234693, rs9340799. Method: We carried out the analysis of 4 polymorphisms located at the promoter of the ESR1 gene (C1 ¼ rs9478245, C2 ¼ rs3138774, C3 ¼ rs2234693, and C4 ¼ rs9340799) in a population of 273 trans women, 226 trans men, and 537 cis gender controls. For SNP polymorphisms, the allele and genotype frequencies were analyzed by c2 test. The strength of the SNP associations with gender incongruence was measured by binary logistic regression. For the STR polymorphism, the mean number of repeats were analyzed by the ManneWhitney U test. Measurement of linkage disequilibrium and haplotype frequencies were also performed. Results: The C2 median repeats were shorter in the trans men population. Genotypes S/S and S/L for the C2 polymorphism were overrepresented in the trans men group (P ¼ .012 and P ¼ .003 respectively). We also found overtransmission of the A/A genotype (C4) in the trans men population (P ¼ .017), while the A/G genotype (C4) was subrepresented (P ¼ .009]. The analyzed polymorphisms were in linkage disequilibrium. In the trans men population, the T(C1)-L(C2)-C(C3)-A(C4) haplotype was overrepresented (P ¼ .019) while the T(C1)-L(C2)-C(C3)-G(C4) was subrepresented (P ¼ .005). Conclusion: The ESR1 is associated with gender incongruence in the trans men populationThis work was supported by grants: ED431B 019/02 (EP), PGC2018-094919-B-C21 (AG), PGC2018-094919-B-C22 (RF), and FPU 15/02558 (JCC)Xunta de Galicia; ED431B 019/0

Convivencia, conflictos y mediación escolar en educación secundaria: estudio de caso

Educational work occurs in a context where interpersonal relationships intervene, which are not exempt from school conflicts. Inappropriate management can trigger a series of discrepancies and adverse reactions, giving rise to aggressions, insults, etc., to the detriment of the school coexistence of Compulsory Secondary Education (ESO) centers, which can lead to school violence. The objectives of the were to evaluate the students' perception of the conflict; the types of conflicts and the mechanisms to resolve them. The participants were 147 students from a Secondary Education Institute (IES) enrolled in 3rd and 4th of ESO and 3rd of the Performance and Learning Improvement Program (PMAR) and 4th of the Curricular Diversification Program ( PDC), between 13 and 18 years old. The instrument was a questionnaire on causes and types of conflicts, elaborated from Ortuño (2014) with the aim of evaluating the students' perception of the conflict; the most common types of conflicts that occur between them and the mechanisms they use to resolve them. The results indicate that the conflicts that occur the most are due to the occupation of the playgrounds; The changes of desks and insulting the classmates and the less frequent ones are insulting the teacher and the destruction of materials. The conclusions highlight the importance of knowing the conflicts that occur daily for proper management without resulting in violence or bullying. As future lines of research, prevention and resolution of school conflicts are highlighted.La labor educativa ocurre en un contexto donde intervienen relaciones interpersonales, que no quedan exentas de conflictos escolares. Una gestión inadecuada puede desencadenar una serie de discrepancias y reacciones adversas, dando lugar a agresiones, insultos, etc., en perjuicio de la convivencia escolar de los centros de Enseñanza Secundaria Obligatoria (ESO), pudiendo derivar en violencia escolar. Los objetivos del  fueron evaluar la percepción de los estudiantes ante el conflicto; los tipos de conflictos  y los mecanismos  para resolverlos. Los participantes fueron 147 estudiantes de un Instituto de Enseñanza Secundaria (IES) Escolarizados en 3.º y 4.º de ESO y 3.º del Programa de Mejora del Rendimiento y Aprendizaje (PMAR) y 4.º del Programa de Diversificación Curricular (PDC), entre 13 y 18 años. El instrumento fue un cuestionario sobre causas y tipos de conflictos, elaborado a partir de Ortuño (2014) con el objetivo de evaluar la percepción de los estudiantes ante el conflicto; los tipos de conflictos más habituales que se producen entre ellos y los mecanismos que utilizan para resolverlos. Los resultados apuntan que los conflictos que más se producen son debidos a la ocupación de las pistas del recreo; los cambios de pupitre e insultar a los compañeros y los menos frecuentes son insultar al profesor y el destrozo de materiales. Las conclusiones destacan la importancia de conocer los conflictos que se producen diariamente para una adecuada gestión sin que deriven en violencia o acoso escolar. Como futuras líneas de investigación se subraya medidas de prevención y solución de conflictos escolares

Low-Frequency Imaginary Impedance at the Superconducting Transition of 2H-NbSe2

The superconducting transition leads to a sharp resistance drop in a temperature interval that can be a small fraction of the critical temperature Tc. A superconductor exactly at Tc is thus very sensitive to all kinds of thermal perturbation, including the heat dissipated by the measurement current. We show that the interaction between electrical and thermal currents leads to a sizable imaginary impedance at frequencies of the order of tens of hertz at the resistive transition of single crystals of the layered material 2H-NbSe2.We explain the result using models developed for transition-edge sensors. By measuring under magnetic fields and at high currents, we find that the imaginary impedance is strongly influenced by the heat associated with vortex motion and out-of-equilibrium quasiparticles

Linear nonsaturating magnetoresistance in the Nowotny chimney ladder compound Ru2Sn3

We present magnetoresistivity measurements in high-quality single crystals of the Nowotny chimney ladder compound Ru2Sn3. We find a linear and nonsaturating magnetoresistance up to 20 T. The magnetoresistance changes with the magnetic field orientation at small magnetic fields, from a positive to a negative curvature. Above 5 T, the magnetoresistance shows no sign of saturation up to 20 T for any measured angle. The shape of the anisotropy in the magnetoresistance remains when increasing temperature and Kohler's rule is obeyed. We associate the linear and nonsaturating magnetoresistance to a small Fermi surface with hot spots, possibly formed as a consequence of the structural transition. We discuss the relevance of electron-electron interactions under magnetic fields and aspects of the topologically nontrivial properties expected in Ru2Sn3This work was supported by the Spanish Research State Agency (FIS2017-84330-R, CEX2018-000805-M, RYC2014-15093, MAT2017-87134-C2-2-R), by the Comunidad de Madrid through the program NANOMAGCOST-CM (Grant No. S2018/NMT-4321) and by the European Research Council PNICTEYES project through Grant Agreement No 67908

Factores que influyen en el proceso de búsqueda de identidad en la adolescencia adoptiva

La adolescencia es un periodo caracterizado por los cambios que llevan a adentrarse en el mundo de la adultez. Una de las principales tareas que los adolescentes deben realizar es encontrar y definir la propia identidad, como un ser único y diferenciado del resto. Cuando el adolescente ha sido adoptado, a dicha construcción de la identidad se le suman más factores de los habituales. En este trabajo se analiza el proceso de búsqueda de identidad en la adolescencia adoptiva a través de los factores de riesgo y protección asociados: perfil de las familias que desean adoptar, estilos educativos, estilo de apego, conocimiento de la condición de adoptado, comunicación de la adopción, búsqueda de los orígenes, vida previa del menor, edad de la adopción y escolarización. Debido al incremento en la actualidad de relaciones problemáticas entre menores adoptados y sus familias adoptivas, en este trabajo se incluye un apartado en el que se tratan las conductas disruptivas de estos menores y un breve análisis sobre la intervención realizada en el ámbito de la adopción

Andreev reflection under high magnetic fields in ferromagnet-superconductor nanocontacts

We study the magnetic-field dependence of the conductance in planar ferromagnet-superconductor nanocontacts created with focused-electron/ion-beam techniques. From the fits of the differential conductance curves in high magnetic fields, we obtain the magnetic field dependences of the superconducting gap and the broadening parameter. Orbital depairing is found to be linear with magnetic field. We evaluate the magnetic field dependence of the quasiparticle density of states, and we compare it with the value obtained by scanning tunneling spectroscopy experimentsThis work was supported by the Spanish Ministry of Science (through projects MAT2008-06567-C02, including FEDER funding) and the Arag´on Regional Government (project E26). S. Sangiao acknowledges financial support from Spanish ME

Estrategias de comunicación en la interacción terapéutica en usuarios de edad avanzada en circustancias de sordera

Introducción: La comunicación es la base para el desarrollo físico, psicológico, social y cultural de todo ser humano. Sin embargo, existen factores que interfieren en el proceso de comunicación, como la sordera o deficiencia auditiva total. Los profesionales de enfermería deben establecer un proceso comunicativo eficaz, brindando una atención integral y de cal idad. Objetivo: Conocer las estrategias de comunicaciónutilizadas en pacientes de edadavanzada en condiciones de deficiencia auditiva total. Metodología: Revisión bibliográfica realizada a través del portal de la Biblioteca Virtual de la Salud (BVS), PubMed y la Biblioteca Cochrane Plus con los descriptores «enfermera» y «sordera» en lenguaje natural y controlado en español einglés y el filtro temporal de diezaños. Resultados: Se obtuvieron un total de 33 artículos, seleccionándose 5 para la revisión. Se identifican diferentesestrategiascomunicativasutilizadas por los profesionales de enfermería ynecesarias en la atención de personas de edad avanzada con deficiencia auditiva total: lenguaje de signos, comunicación no verbal, uso de la escritura, realización de dibujos y creación de programas informáticos para facilitar la comunicación. Conclusión: El uso de estrategias de comunicación entre el profesional de enfermería y los usuarios de edad avanzada con sordera es fundamental. El establecimiento de áreas de mejora en la formación comunicativa de los profesionales puede facilitar la relación terapéutica e interferir positivamente en la calidad asistencial.Introduction: Communication is the basis for the physical, psychological, social and cultural development of every human being. However, some factors can interfere with the communication process, such as deafness or total hearing impairment. Nursing professionals must establish an effective communicative process, providing comprehensive and quality care. Objective: To know the communication strategies in elderly patients with total hearing impairment Methodology: A bibliographic review was carried out throughBiblioteca Virtual de la Salud (BVS), PubMed and The Cochrane Library.Descriptors used were "nurse" and "deafness". Bothin natural and controlled language. Idiomatic filters (Spanish and English) and a time limit filter (10 years) were also used. Results:33 articles were obtained, but just 5 were selected for the review. The articles identify the following communication strategies used by nursing professionals that are necessary for the care of elderly people with total hearing disability, used by nursing professionals: sign language, non-verbal communication, use of writing, creation of drawings and creation of computer programs to facilitate communication. Conclusion: The use of communication strategies between the nursing professional and elderly people with deafness is fundamental. The establishment of areas of improvement in the communicative training of professionals can facilitate the therapeuti

Vortex creep at very low temperatures in single crystals of the extreme type-II superconductor Rh9In4 S4

We image vortex creep at very low temperatures using scanning tunneling microscopy in the superconductor Rh9In4S4 (Tc=2.25K). We measure the superconducting gap of Rh9In4S4, finding Δ≈0.33meV, and image a hexagonal vortex lattice up to close to Hc2, observing slow vortex creep at temperatures as low as 150 mK. We estimate thermal and quantum barriers for vortex motion and show that thermal fluctuations likely cause vortex creep, in spite of being at temperatures T/Tc<0.1. We study creeping vortex lattices by making images during long times and show that the vortex lattice remains hexagonal during creep with vortices moving along one of the high-symmetry axes of the vortex lattice. Furthermore, the creep velocity changes with the scanning window suggesting that creep depends on the local arrangements of pinning centers. Vortices fluctuate on small-scale erratic paths, indicating that the vortex lattice makes jumps trying different arrangements during its travel along the main direction for creep. The images provide a visual account of how vortex lattice motion maintains hexagonal order, while showing dynamic properties characteristic of a glassWe acknowledge R. Willa and V. G. Kogan for helpful and critical comments and discussions with S. Vieira. We wish to acknowledge the support of the Departamento Administrativo de Ciencia, Tecnología e Innovación, COLCIENCIAS (Colombia) Programa Doctorados en el Exterior Convocatoria 568-2012. We further acknowledge support by the Spanish Ministry of Economy and Competitiveness (Grants No. FIS2014-54498-R and No. MDM-2014-0377), the Comunidad de Madrid through program Nanofrontmag-CM (Grant No. S2013/MIT-2850), the EU (IG, European Research Council PNICTEYES Grant Agreements No. 679080, No. FP7-PEOPLE-2013-CIG 618321, and No. Cost MP-1201), and by Axa Research Fund. SEGAINVEX-UAM and Banco Santander are also acknowledged. Work done at the Ames Laboratory was supported by the U.S. Department of Energy, Office of Basic Energy Science, Division of Materials Sciences and Engineering. Ames Laboratory is operated for the U.S. Department of Energy by Iowa State University under Contract No. DE-AC02-07CH1135